Using software architecture techniques to support the modular certification of safety-critical systems

• Authors: Tim Kelly
• Venue: SCS '06 Proceedings of the eleventh Australian workshop on Safety critical systems and software - Volume 69
• Year: 2007

In software engineering the role of software architecture as a means of managing complexity and achieving emergent qualities such as modifiability is increasingly well understood. In this paper we demonstrate how many principles from the field of software architecture can be brought across to the field of safety case management in order to help manage complex safety cases. Traditional approaches to certification of modular systems as a statically defined configuration of components can result in a large certification overhead being associated with any module update or addition. A more promising approach is to attempt to establish a modular, compositional, approach to constructing safety cases that has a correspondence with the modular structure of the underlying architecture. This paper establishes the mechanisms for managing and representing safety cases as a composition of safety case 'modules'. Having defined the concept of a modular safety case, the paper also describes principles for their definition and evaluation. An example generic modular safety case architecture for Integrated Modular Avionics (IMA) based systems is presented as a means of illustrating the concepts defined.